The present invention generally relates to a flow control valve, and more particularly relates to a thermally-actuated flow-restrictor device for an aircraft galley insert.
Aircraft galley inserts or appliances that contain tanks of hot water, such as coffee or tea beverage makers, are generally installed in an aircraft galley using an open plumbing system. In this type of system, water from a potable water supply in the aircraft fills the tank of the galley insert when the water is pressurized and drains from the tank when the pressure is relieved. This type of system is intended to prevent formation of excessively high pressure inside the tank when the water in the tank is heated by the aircraft galley insert, such as when dispensing hot drinks.
However, in an open plumbing system, the tank of the galley insert may experience a drop in pressure after the water in the tank is heated. In the case of beverage makers, where water in the tank is usually heated to 180 degrees Fahrenheit or higher, any drop in pressure in the tank may result in a possible backflow of hot water into the aircraft galley's plumbing system. Consequently, crew members in the galley may be at risk of harm if they use a galley sink connected to the aircraft galley's plumbing system, since extremely hot water may unexpectedly expel from the sink faucet as a result of the backflow from the beverage maker.
Conventional backflow prevention mechanisms or flow-restrictor devices provide inadequate solutions to this problem. For example, check valves are designed to prevent complete backflow of water, and therefore do not typically provide a sufficient outlet for relief of pressure of hot, highly pressurized water. Without a sufficient outlet for the pressure, a crew member would be at risk when he or she uses the beverage maker, since the hot, highly pressurized water would be expelled from the beverage maker at an unexpectedly high rate of speed. Additionally, other types of valves, such as thermal valves or electrically operated valves, are typically large and heavy and thus generally must be installed directly in the aircraft galley's plumbing system, which can be very costly to set up and maintain.
Hence, there is a need for a flow-restrictor device for an aircraft galley insert that prevents excessive backflow of hot water from the galley insert into the aircraft galley's plumbing system, while also preventing the galley insert from becoming highly pressurized. There is also a need for a flow-restrictor device that is lightweight, compact, and capable of fitting within a standard aircraft galley insert without requiring external installation directly in the aircraft galley's plumbing system, and that does not require electricity for operation. The present invention meets this and other needs.